| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting device capable of preventing unusual heating and breakage of the lighting device. SOLUTION: By providing an integrating circuit C1. Ra in a drive circuit for a transistor TR1 for triggering an FET Q1 connected to filament terminals f2, f2' of a fluorescent lamp FL, the timing of its lighting is delayed, thereby preventing an overvoltage from being imposed on the FET Q1, when power is inputted. By providing a differentiation circuit C4, R5 for driving the triggering transistor TR1 by a steep peak value of a preheating current Id, the lighting time is shortened, lighting failure is avoided, and deterioration of a discharge tube is prevented, By providing a timer circuit R3, C3 for turning off the FET Q1 after a fixed period of time has passed. a lighting circuit is turned off at lighting failure, thus preventing the lighting device from being broken. |
